Loud Popping Sound from Class D Amp Soundbar

[panabiker]

I have a 2 yo. soundbar that started making annoying popping and buzzing sound (like AC hum but with more harmonics). I replaced some electrolytic caps that looked a little bulged. The buzzing sound went away but the popping still exits. Some times it pops as frequently as every few seconds. It does not matter which input is selected but loudness does change with volume control. Any idea where I should look into, or what could possibly be the source of the pops? The amplifier is class D, which may or may not be relevant to the problem.

 

[M Philbrook]

In article <8c45e5fb-88c2-4e0d-a29b-5dc7d3d87ba0@googlegroups.com>,
gangh58@gmail.com says...

I have a 2 yo. soundbar that started making annoying popping and buzzing sound (like AC hum but with more harmonics). I replaced some electrolytic caps that looked a little bulged. The buzzing sound went away but the popping still exits. Some times it pops as frequently as every few seconds. It does not matter which input is selected but loudness does change with volume control. Any idea where I should look into, or what could possibly be the source of the pops? The
amplifier is class D, which may or may not be relevant to the problem.

This is not a repair group however, I too had such a case with
a different product. The IC being used for the Audio section
served as the power amp and preamp. The volume control is
part of the IC.

It's possible you have a bad IC or you have a small cap connected
to it that is also bad and getting into the bias of the IC.

I would look for more caps. Also, make sure the IC isn't getting
hot.

P.S.
A scope with external trigger sweep set to noise pulse works great
for this. You find a audioless broadcast and crank up the volume,
probe around for the problem. I think you'll find it coming from a
bad cap or bad joint.

Jamie

 

[Jim Thompson]

On Sun, 9 Aug 2015 12:48:08 -0700 (PDT), panabiker <gangh58@gmail.com>
wrote:

>I have a 2 yo. soundbar that started making annoying popping and buzzing sound (like AC hum but with more harmonics). I replaced some electrolytic caps that looked a little bulged. The buzzing sound went away but the popping still exits. Some times it pops as frequently as every few seconds. It does not matter which input is selected but loudness does change with volume control. Any idea where I should look into, or what could possibly be the source of the pops? The amplifier is class D, which may or may not be relevant to the problem.

I had that (popping) problem at the previous house with a TV set in my
office. I blamed the set, but it turned out to be a ratty connection
to the AC outlet.

...Jim Thompson
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